U.S. patent application number 11/448831 was filed with the patent office on 2007-02-01 for nitride-based compound semiconductor light emitting device and method of fabricating the same.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Tae-hoon Jang.
Application Number | 20070023775 11/448831 |
Document ID | / |
Family ID | 37674419 |
Filed Date | 2007-02-01 |
United States Patent
Application |
20070023775 |
Kind Code |
A1 |
Jang; Tae-hoon |
February 1, 2007 |
Nitride-based compound semiconductor light emitting device and
method of fabricating the same
Abstract
A nitride-based semiconductor light emitting device with
improved characteristics of ohmic contact to an n-electrode and a
method of fabricating the same are provided. The nitride-based
semiconductor light emitting device includes an n-electrode, a
p-electrode, an n-type compound semiconductor layer, and an active
layer and a p-type compound semiconductor layer formed between the
n- and p-electrodes. The n-electrode includes: a first electrode
layer formed of at least one element selected from the group
consisting of Pd, Pt, Ni, Co, Rh, Ir, Fe, Ru, Os, Cu, Ag, and Au;
and a second electrode layer formed on the first electrode layer
using a conductive material containing at least one element
selected from the group consisting of Ti, V, Cr, Zr, Nb, Hf, Ta,
Mo, W, Re, Ir, Al, In, Pb, Ni, Rh, Ru, Os, and Au.
Inventors: |
Jang; Tae-hoon; (Seoul,
KR) |
Correspondence
Address: |
BUCHANAN, INGERSOLL & ROONEY PC
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
37674419 |
Appl. No.: |
11/448831 |
Filed: |
June 8, 2006 |
Current U.S.
Class: |
257/99 |
Current CPC
Class: |
H01L 33/40 20130101;
H01L 33/0095 20130101; H01L 33/32 20130101 |
Class at
Publication: |
257/099 |
International
Class: |
H01L 33/00 20060101
H01L033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 30, 2005 |
KR |
10-2005-0070030 |
Claims
1. A nitride-based compound semiconductor light emitting device
including an n-electrode, a p-electrode, and an n-type compound
semiconductor layer, an active layer and a p-type compound
semiconductor layer formed between the n-electrode and the
p-electrode, wherein the n-electrode comprises: a first electrode
layer formed of at least one element selected from the group
consisting of Pd, Pt, Ni, Co, Rh, Ir, Fe, Ru, Os, Cu, Ag, and Au;
and a second electrode layer formed on the first electrode layer
using a conductive material containing at least one element
selected from the group consisting of Ti, V, Cr, Zr, Nb, Hf, Ta,
Mo, W, Re, Ir, Al, In, Pb, Ni, Rh, Ru, Os, and Au.
2. The device of claim 1, wherein the n-electrode is annealed in a
temperature range of approximately 200.degree. C. to 900.degree.
C.
3. The device of claim 1, wherein the active layer, the p-type
compound semiconductor, and the p-electrode are sequentially formed
on a first surface of the n-type compound semiconductor layer, and
wherein the n-electrode is formed on a second surface of the n-type
compound semiconductor layer.
4. The device of claim 3, wherein the n-type compound semiconductor
layer is an n-GaN layer.
5. The device of claim 4, wherein the second surface of the n-GaN
layer is a Ga-polar surface, N-polar surface, or non-polar
surface.
6. The device of claim 1, further comprising a GaN substrate,
wherein the n-type compound semiconductor layer, the active layer,
the p-type compound semiconductor layer, and the p-electrode are
sequentially formed on a first surface of the GaN substrate, and
wherein the n-electrode is formed on a second surface of the GaN
substrate.
7. The device of claim 6, wherein the second surface of the GaN
substrate is a Ga-polar surface, N-polar surface, or non-polar
surface.
8. The device of claim 1, further comprising a sapphire substrate,
wherein the n-type compound semiconductor layer, the active layer,
the p-type compound semiconductor layer, and the p-electrode are
sequentially formed on the sapphire substrate, and wherein the
n-type compound semiconductor layer has a stepped surface and the
n-electrode is formed on the stepped surface.
9. The device of claim 8, wherein the n-type compound semiconductor
layer is an n-GaN layer.
10. The device of claim 9, wherein the stepped surface of the n-GaN
layer is a Ga-polar surface, an N-polar surface, or a non-polar
surface.
11. The device of claim 1, wherein the first electrode layer is
formed to a thickness of approximately 1 to 1,000 .ANG..
12. The device of claim 1, wherein the p-type compound
semiconductor layer includes a p-GaN layer.
13. A method of fabricating a nitride-based compound semiconductor
light emitting device, the method comprising: preparing a GaN
substrate; sequentially forming an n-type compound semiconductor
layer, an active layer, a p-type compound semiconductor layer, and
a p-electrode on a first surface of the GaN substrate; and forming
an n-electrode on a second surface of the GaN substrate, wherein
the forming of the n-electrode comprises: forming a first electrode
layer of at least one element selected from the group consisting of
Pd, Pt, Ni, Co, Rh, Ir, Fe, Ru, Os, Cu, Ag, and Au; forming a
second electrode layer on the first electrode layer using a
conductive material containing at least one element selected from
the group consisting of Ti, V, Cr, Zr, Nb, Hf, Ta, Mo, W, Re, Ir,
Al, In, Pb, Ni, Rh, Ru, Os, and Au; and annealing the first and
second electrode layers.
14. The method of claim 13, wherein the second surface of the GaN
substrate is a Ga-polar surface, N-polar surface, or non-polar
surface.
15. The method of claim 14, wherein the first electrode layer is
formed to a thickness of approximately 1 to 1,000 .ANG..
16. The method of claim 13, wherein the annealing is performed in a
temperature range of approximately 200.degree. C. to 900.degree.
C.
17. The method of claim 16, wherein the n-type compound
semiconductor layer and the p-type compound semiconductor layer
include an n-GaN layer and a p-GaN layer, respectively.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATION
[0001] This application claims the benefit of Korean Patent
Application No. 10-2005-0070030, filed on Jul. 30, 2005, in the
Korean Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND OF THE DISCLOSURE
[0002] 1. Field of the Disclosure
[0003] The present disclosure relates to a nitride-based compound
semiconductor device and a method of fabricating the same, and more
particularly, to a nitride-based compound semiconductor device
having improved characteristics of ohmic contact to an n-electrode
and a method of fabricating the same.
[0004] 2. Description of the Related Art
[0005] Laser diodes (LDs) or light-emitting diodes (LEDs) are
commonly known as nitride-based semiconductor light emitting
devices. LEDs are semiconductor devices that emit light of specific
wavelength as electrons move from a high energy to low energy level
when electricity is applied. LEDs are widely used in various
applications to create light such as green light on the mother
board when a hard disc spins, light on an electronic display board
installed at buildings, or blinking light on a cellular phone. The
LEDs have emerged as new light-emitters that provide about 1/12 the
power consumption, more than 100 times the life span, and more than
1,000 times the reaction rate to electricity when compared to
conventional bulbs. They are also receiving considerable attention
as a promising display means such as electronic display boards
because of the high brightness and low power consumption. LEDs emit
light of different colors depending on the type of compound
semiconductor materials used (e.g., gallium phosphide (GaP) or
gallium arsenide (GaAs)). In particular, LEDs emitting red or green
light have been widely used in various industrial applications as
well as in home electronic appliances for over several decades.
[0006] LEDs are classified into top-emitting light-emitting diodes
(TLEDs) and flip-chip LEDs (FCLEDs) depending on the direction in
which light exits. In commonly used TLEDs, light exits through a
p-electrode forming an ohmic contact with a p-type compound
semiconductor layer. The p-electrode is typically formed of nickel
(Ni)/gold (Au) on the p-type compound semiconductor layer. However,
a TLED using a semi-transparent Ni/Au p-electrode has a low light
utilization efficiency and low brightness. In a FCLED, light
generated in an active layer is reflected by a reflective electrode
and the reflected light is emitted through a substrate. The
reflective electrode is made of a highly light reflective material
such as silver (Ag), aluminum (Al), or rhodium (Rh). The FCLED
using the reflective electrode can provide a high light utilization
efficiency and high brightness.
[0007] A conventional n-electrode in a LED or LD is made of an
Al--Ti based material that should be annealed at a high temperature
above 600.degree. C. In particular, the Al--Ti based material has
difficulty in forming an ohmic contact on an N-polar surface of a
freestanding GaN substrate. More specifically, conventionally Ti/Al
or Al/Ti are deposited on the GaN substrate and then are annealed
at high temperature above 600.degree. C. to form an ohmic contact
to an n-electrode. However, annealing at high temperature above
600.degree. C. may cause thermal damage to layers formed in a stack
before annealing. To prevent this problem, conventionally an
n-electrode is formed on a GaN substrate before forming thereon an
n-type compound semiconductor layer, an active layer, a p-type
compound semiconductor layer, and a p-electrode. As described
above, another drawback of an Al--Ti based material is that it can
form an ohmic contact only on a Ga-polar surface. It has been known
that the Al--Ti based material has difficulty in forming an ohmic
contact on the N-polar surface. Thus, to overcome these problems,
there is an urgent need to develop an n-electrode material that can
improve the characteristics of ohmic contact to the n-electrode and
improve the structure of the n-electrode.
SUMMARY OF THE DISCLOSURE
[0008] The present invention may provide a nitride-based compound
semiconductor device with improved characteristics of ohmic contact
to an n-electrode and a method of fabricating the same.
[0009] According to an aspect of the present invention, there may
be provided a nitride-based compound semiconductor light emitting
device including an n-electrode, a p-electrode, an n-type compound
semiconductor layer, and an active layer and a p-type compound
semiconductor layer formed between the n-electrode and the
p-electrode. The n-electrode includes: a first electrode layer
formed of at least one element selected from the group consisting
of Pd, Pt, Ni, Co, Rh, Ir, Fe, Ru, Os, Cu, Ag, and Au; and a second
electrode layer formed on the first electrode layer using a
conductive material containing at least one element selected from
the group consisting of Ti, V, Cr, Zr, Nb, Hf, Ta, Mo, W, Re, Ir,
Al, In, Pb, Ni, Rh, Ru, Os, and Au.
[0010] The n-electrode is annealed in a temperature range of
approximately 200.degree. C. to 900.degree. C. The first electrode
layer is formed to a thickness of approximately 1 to 1,000 .ANG..
The p-type compound semiconductor layer includes a p-GaN layer.
[0011] The active layer, the p-type compound semiconductor, and the
p-electrode may be sequentially formed on a first surface of the
n-type compound semiconductor layer and the n-electrode is formed
on a second surface thereof. The n-type compound semiconductor
layer is an n-GaN layer and a second surface of the n-GaN layer is
a Ga-polar surface, an N-polar surface, or a non-polar surface.
[0012] The nitride-based compound semiconductor light emitting
device further includes a GaN substrate. The n-type compound
semiconductor layer, the active layer, the p-type compound
semiconductor layer, and the p-electrode may be sequentially formed
on a first surface of the GaN substrate and the n-electrode may be
formed on a second surface thereof. The second surface of the GaN
substrate is a Ga-polar surface, an N-polar surface, or a non-polar
surface.
[0013] The nitride-based compound semiconductor light emitting
device may further include a sapphire substrate. In this instance,
the n-type compound semiconductor layer, the active layer, the
p-type compound semiconductor layer, and the p-electrode may be
sequentially formed on the sapphire substrate and the n-type
compound semiconductor layer may have a stepped surface on which
the n-electrode is formed.
[0014] According to another aspect of the present invention, there
may be provided a method of fabricating a nitride-based compound
semiconductor light emitting device, including the steps of:
preparing a GaN substrate; sequentially forming an n-type compound
semiconductor layer, an active layer, a p-type compound
semiconductor layer, and a p-electrode on a first surface of the
GaN substrate; and forming an n-electrode on a second surface of
the GaN substrate.
[0015] The step of forming the n-electrode includes the steps of:
forming a first electrode layer of at least one element selected
from the group consisting of Pd, Pt, Ni, Co, Rh, Ir, Fe, Ru, Os,
Cu, Ag, and Au; forming a second electrode layer on the first
electrode layer using a conductive material containing at least one
element selected from the group consisting of Ti, V, Cr, Zr, Nb,
Hf, Ta, Mo, W, Re, Ir, Al, In, Pb, Ni, Rh, Ru, Os, and Au; and
annealing the first and second electrode layers.
[0016] The second surface of the GaN substrate is a Ga-polar
surface, an N-polar surface, or a non-polar surface. The first
electrode layer is formed in a thickness of approximately 1 to
1,000 .ANG.. The annealing is performed in a temperature range of
approximately 200.degree. C. to 900.degree. C.
[0017] The n-type compound semiconductor layer and the p-type
compound semiconductor layer may include an n-GaN layer and a p-GaN
layer, respectively.
[0018] The present invention can provide a nitride-based compound
semiconductor light emitting device with improved characteristics
of ohmic contact to the n-electrode.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above and other features and advantages of the present
invention will be described in detailed exemplary embodiments
thereof with reference to the attached drawings in which:
[0020] FIG. 1 is a schematic cross-sectional view of a
nitride-based compound semiconductor light emitting device
according to an embodiment of the present invention;
[0021] FIG. 2 is a schematic cross-sectional view of a
nitride-based compound semiconductor light emitting device
according to another embodiment of the present invention;
[0022] FIGS. 3A-3E are flow charts illustrating the steps of a
method of fabricating a nitride-based compound semiconductor light
emitting device according to an embodiment of the present
invention; and
[0023] FIG. 4 is a graph illustrating ohmic contact characteristics
of a light-emitting diode (LED) using a conventional Ti/Al
n-electrode and a LED using a Pd/Ti/Al n-electrode according to the
present invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0024] A nitride-based compound semiconductor light emitting device
and a method of fabricating the same according to exemplary
embodiments of the present invention will now be described in
detail with reference to the accompanying drawings. In the
drawings, the thicknesses of layers and regions are exaggerated for
clarity.
[0025] FIG. 1 is a schematic cross-sectional view of a
nitride-based compound semiconductor light emitting device
according to an embodiment of the present invention. Referring to
FIG. 1, the nitride-based compound semiconductor light emitting
device according to the current embodiment of the present invention
includes an n-electrode 31, a p-electrode 20, and a n-type compound
semiconductor layer 12, an active layer 14 and a p-type compound
semiconductor layer 16 formed between the n-electrode 31 and the
p-electrode 20. More specifically, the n-type compound
semiconductor layer 12, the active layer 14, the p-type compound
semiconductor layer 16, and the p-electrode 20 are sequentially
formed on a first surface 10a of a GaN substrate 10. The
n-electrode 31 is formed on a second surface 10b of the GaN
substrate 10 and includes a first electrode layer 31a formed of at
least one element selected from the group consisting of Pd, Pt, Ni,
Co, Rh, Ir, Fe, Ru, Os, Cu, Ag, and Au and a second electrode layer
31b formed on the first electrode layer 31b using a conductive
material containing at least one element selected from the group
consisting of Ti, V, Cr, Zr, Nb, Hf, Ta, Mo, W, Re, Ir, Al, In, Pb,
Ni, Rh, Ru, Os, and Au. The second electrode layer 31b may have a
multilayer structure such as Ti/Al or Al/Ti layer. The n-electrode
31 is annealed at temperature of approximately 200.degree. C. to
900.degree. C. The first electrode layer 31a may be formed in a
thickness of approximately 1 to 1,000 .ANG.. The second surface 10b
of the GaN substrate 10 may be a Ga-polar surface, an N-polar
surface, or a non-polar surface.
[0026] The material of the first electrode layer 31a such as Pd,
Pt, Ni, Co, Rh, Ir, Fe, Ru, Os, Cu, Ag, or Au is highly reactive
with the second surface 10b of the GaN substrate 10. For example,
when the first and second electrode layers 31a and 31b are formed
of Pd and Ti/Al, respectively, Pd reacts with Ga on the GaN
substrate 10 to form Pd-gallide while Ti or Al reacts with N on the
GaN substrate 10 to form AlN or TiN. Thus, characteristics of ohmic
contact to the n-electrode 31 can be improved. In particular, the
n-electrode 31 has excellent ohmic contact characteristics on the
Ga-polar surface as well as on the N-polar surface that are
conventionally known to have difficulty in forming an ohmic
contact. The material of the n-electrode 31a is also highly
reactive to form a uniform ohmic contact when the width of a
contact dimension is small.
[0027] Because the annealing temperature for the n-electrode 31 can
be reduced to below 600.degree. C. during manufacturing of the
nitride-based compound semiconductor light emitting device having
the above-mentioned configuration, it is possible to reduce thermal
damage to a stack of other layers formed before annealing, i.e.,
the n-type compound semiconductor layer 12, the active layer 14,
the p-type compound semiconductor layer 16, and the p-electrode
20.
[0028] The n-type compound semiconductor layer 12 is made of n-GaN
based III-V nitride semiconductor material, in particular, n-GaN,
or other III-IV compound semiconductor material capable of inducing
laser oscillation (lasing). The n-type compound semiconductor layer
12 may include a lower cladding layer (not shown). The lower
cladding layer may be made of n-GaN/AlGaN having a predetermined
refractive index or other compound semiconductor material capable
of inducing lasing.
[0029] The active layer 14 may be made of any material capable of
inducing lasing, preferably, a material capable of inducing
oscillation of a laser with low threshold current and stable
transverse mode characteristics. The active layer 14 may be formed
of InxAlyGa1-x-yN(0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, and
x+y.ltoreq.1) that is a GaN-based III-V nitride compound
semiconductor material containing a predetermined percentage of Al.
The active layer 14 may have a single quantum well (SQW) or
multiquantum well (MQW) structure or other known structure.
[0030] The p-type compound semiconductor layer 16 may be formed of
a p-GaN based III-V nitride semiconductor material, in particular,
p-GaN, or other III-IV compound semiconductor material capable of
inducing laser oscillation (lasing). The p-type compound
semiconductor layer 16 may include an upper cladding layer (not
shown). The upper cladding layer may be made of p-GaN/AlGaN having
a predetermined refractive index or other compound semiconductor
material capable of inducing lasing.
[0031] The p-electrode 20 is mainly composed of Ni/Au bilayer
formed on the p-type compound semiconductor layer 16 and forms an
ohmic contact with the p-type compound semiconductor layer 16.
[0032] The nitride-based compound semiconductor light emitting
device having the above-mentioned configuration according to the
present invention can provide improved characteristics of the ohmic
contact to the n-electrode 31 and output power characteristics.
While in the above description, the GaN substrate 10 and the n-type
compound semiconductor layer 12 are separate independent
components, the GaN substrate 10 may be incorporated into the
n-type compound semiconductor layer 12. In this instance, an active
layer, a p-type semiconductor layer, and a p-electrode may be
sequentially formed on a first surface of an n-type compound
semiconductor layer while an n-electrode may be formed on a second
surface of the n-type compound semiconductor layer.
[0033] FIG. 2 is a schematic cross-sectional view of a
nitride-based compound semiconductor light emitting device
according to another embodiment of the present invention. Like
reference numerals in FIGS. 1 and 2 denote like elements, and thus
their description is omitted.
[0034] Referring to FIG. 2, the nitride-based compound
semiconductor light emitting device further includes a sapphire
substrate 11, and an n-type compound semiconductor layer 12, an
active layer 14, a p-type compound semiconductor layer 16, and a
p-electrode 20 sequentially formed on the sapphire substrate 11.
The n-type compound semiconductor layer 12 is etched to a
predetermined depth to form a stepped surface 12a on one side
thereof and the n-electrode 31 is disposed on the stepped surface
12a. The stepped surface 12a of the n-type compound semiconductor
layer 12 may be a Ga-polar surface, N-polar surface, or non-polar
surface.
[0035] FIGS. 3A-3E are flow charts illustrating the steps of a
method of fabricating a nitride-based compound semiconductor light
emitting device according to an embodiment of the present
invention.
[0036] Referring to FIGS. 3A and 3B, the GaN substrate 10 is
prepared and an n-type compound semiconductor layer 12, an active
layer 14, a p-type compound semiconductor layer 16, and a
p-electrode 20 are sequentially formed on a first surface 10a of
the GaN substrate 10. Because the n-type compound semiconductor
layer 12, the active layer 14, the p-compound semiconductor layer
16, and the p-electrode 20 have the same structures as or are
formed of the same materials as described above using commonly
known techniques, detailed explanations thereof are not included.
For example, each layer may be formed using a thin film deposition
technique, such as chemical vapor deposition (CVD), metalorganic
CVD (MOCVD), plasma-enhanced CVD (PECVD), or physical vapor
deposition (PVD).
[0037] Referring to FIGS. 3A-3E, first and second electrode layers
30a and 30b are sequentially formed on a second surface 10b of the
GaN substrate 10 and are heat treated using a technique such as
annealing to form the n-electrode 31. The second surface 10b of the
GaN substrate 10 may be a Ga-polar surface, an N-polar surface, or
a non-polar surface.
[0038] First, referring to FIG. 3C, the first electrode layer 30a
is formed of at least one element selected from the group
consisting of Pd, Pt, Ni, Co, Rh, Ir, Fe, Ru, Os, Cu, Ag, and Au in
a thickness of approximately 1 to 1,000 .ANG.. The second electrode
layer 30b may be formed of a conductive material containing at
least one element selected from the group consisting of Ti, V, Cr,
Zr, Nb, Hf, Ta, Mo, W, Re, Ir, Al, In, Pb, Ni, Rh, Ru, Os, and Au
in any thickness. The second electrode layer 30b may have a
multi-layer structure. For example, the first and second electrode
layers 31a and 31b may be formed of Pd and Ti/Al, respectively.
[0039] Subsequently, referring to FIGS. 3D and 3E, the first and
second electrode layers 30a and 30b are heat treated using
annealing to form an n-electrode 31 having improved ohmic contact
characteristics. While the annealing can be performed in the
temperature range of approximately 200.degree. C. to 900.degree.
C., it may be performed in a lower temperature range, e.g.,
approximately 200.degree. C. to 600.degree. C.
[0040] Because annealing temperature of the n-electrode 31 can be
reduced to below 600.degree. C. during manufacturing of the
nitride-based compound semiconductor light emitting device, it is
possible to reduce thermal damage to a stack of other layers formed
before annealing, i.e., the n-type compound semiconductor layer 12,
the active layer 14, the p-type compound semiconductor layer 16,
and the p-electrode 20. This enables the n-type compound
semiconductor layer 12, the active layer 14, the p-type compound
semiconductor layer 16, and the p-electrode 20 to be sequentially
formed on the GaN substrate 10 prior to formation of the
n-electrode 31. Thus, it is possible to more readily fabricate the
nitride-based compound semiconductor light emitting device than a
conventional device.
[0041] The nitride-based compound semiconductor light emitting
devices and methods of fabricating the same according to
embodiments of the present invention can be readily applied to the
fabrication of optical devices such as laser diodes (LDs) or light
emitting diode (LEDs).
[0042] FIG. 4 is a graph illustrating ohmic contact characteristics
of a GaN LED using a conventional Ti/Al n-electrode and a GaN LED
using a Pd/Ti/Al n-electrode according to the present invention.
When the n-electrodes are annealed in a low temperature range of
approximately 400.degree. C. to 600.degree. C., the LED of the
present invention has improved ohmic contact characteristics over
the conventional LED.
[0043] The present invention can provide a nitride-based compound
semiconductor light emitting device with improved characteristics
of ohmic contact to an n-electrode. In particular, because the
annealing temperature for the n-electrode 31 can be reduced to
below 600.degree. C. during manufacturing of the nitride-based
compound semiconductor light emitting device having the
above-mentioned configuration, thermal damage to a stack of other
layers formed before annealing can also be reduced. Thus, because
an n-type compound semiconductor layer, an active layer, a p-type
compound semiconductor layer, and a p-electrode can be sequentially
formed on the GaN substrate 10 prior to formation of the
n-electrode 31, it is possible to more easily fabricate the
nitride-based compound semiconductor light emitting device than a
conventional device.
[0044] In the present invention, the n-electrode 31 has excellent
ohmic contact characteristics on a Ga-polar surface as well as on
an N-polar surface that is typically known to have difficulty in
forming an ohmic contact. In particular, the material of the
n-electrode is also highly reactive to form a uniform ohmic contact
when the width of a contact dimension is small. The nitride-based
compound semiconductor light emitting devices and methods of
fabricating the same according to embodiments of the present
invention can be readily applied to the fabrication of optical
devices such as LDs or LEDs.
[0045] While the present invention has been particularly shown and
described with reference to exemplary embodiments thereof to aid in
the understanding thereof, the embodiments are presented by way of
example, not as a limitation. The present invention is not limited
to the structure and arrangements described and shown above. That
is, it will be understood by those of ordinary skill in the art
that various changes in form and details may be made therein
without departing from the spirit and scope of the present
invention as defined by the following claims.
* * * * *